Phase 0 - Customer and Research

For this project the customer approached me through a common friend of mine that I worked with at Camosun College. For the privacy of the customer I will not mention their name but I will instead mention that they are a member of a Southern Vancouver Island Search and Rescue organization. He came to me with the idea that in his district the local fire department uses opticom transmitters on high priority to beat traffic jams.

My customer did not want to impede emergency vehicles but wanted to find a way to help alleviate these traffic burdens. The Opticom system they use was much too costly and therefore with permission from the local emergency detachment and municipality was granted permission to use the low priority signal to respond to search and rescue emergencies.

Our first goal was to take a look at what was commercially available and what the budget for the project was. Because of the expensive of a high tech system was in the thousands of dollars we searched to find a better solution. After weeks of research it became clear that we were going to have to build our own system. A word of caution, without clearance from local municipalities and the proper permits this would be illegal. I ensure you that all of these requirements were in place before this project started.

Phase 1 - Part Selection

The parts list was quite simple for this project but the software to control this device would have to be quite complex. The first and most important part was the use of infrared LED's which would be capable of registering on the Opticom recievers. We went to the known hobby site, Sparkfun, to find the part that we needed. The part used was the Power IR kit which included everything that was needed for taking a pulsed microcontroller signal and output at 50mA on the LED.

The next part to find was the microcontroller to use in the project. The original idea was to write all of the code in C so that we could accurately control the clock speed and produce the correct waveforms required to create the encoded signal. This plan of action ended up failing because one of the reqirements was to be able to change the code if required. The device was given a unique code for the strobe pattern and if that code needed to be changed the customer wanted the ability to program it without taking it apart. I then looked at some USB capable processors that would do the job and then looked at the PCB layout. After I submitted a price quote he decided that he wanted something off the shelf instead of custom. My mind instantly clicked onto an Arduino solution. The board we decided on was an Arduino Pro Mini from Sparkfun.

Battery power in the case was not a problem as it would always be connected to car power. A 5.5mm Power Jack and Adapter were found at the Quale Electronics. USB connectivity is supplied by a Breakout Board that has a mini-usb connector and converts USB to serial to talk to the Arduino.

The last thing required for the project was a case to house everything inside. We wanted something discrete and compact so we came up with the idea of using a dead automotive GPS device that was large enough to house all of the electronics. The model is the Garmin Nuvi 680. We decided not to use any of the components other than the case to hide the contents of the project. The LCD provided a nice cover to hide everything. The power button on top provided us an activation button for the system.

Phase 2 - Prototype

The first thing we picked up was the dead GPS. We aquired three dead GPS's from a seller on Used Victoria who used them while travelling but the batteries no longer held a charge. We picked up three devices for $30 which will be used for other devices in the future so we budgeted at $10 each.

As you can see from Part 1, we ordered a bunch of things from Sparkfun, luckily in the part selection phase we ordered everything at once and we got a good deal on shipping. Everything that we required to make one unit cost us $42 and change. There were some other parts ordered at the same time so it was a worthwhile shipment.

The last thing that had to be purchased for this project was a set of tools from NewPower99. I am sure that we could have found tools at the local hardware store and made a set of the tools that we required. But in order to create a proper repair kit I went with a company that I have used in the past to get the tools required. We ordered an extra battery for one of the GPS's to see if we could bring one back to life and allow it to function again. Total cost for the tools, battery and shipping was about $35.

Once everything arrived I soldered up the Power IR kit and tested it's function. IR Light cannot be seen by the naked eye so when running some tests I used my Nikon D5100 in video mode to capture video. That video can be seen here. Once all the parts were in it was easy to get everything assembled and put into the GPS. A small hole had to be cut where the speaker was to feed one of the LED's out so that the range was extended.

Phase 3 - Software

I have to tell you that no example code for this project will be available because in the wrong hands this information could be used illegally.

Phase 4 - Assembly

Phase 5 - Launch

Phase 6 - Documentation